Pressure-armed impact-fired fuse



Feb. 2l, 1950 G. E. BREEZE ET AL PRESSURE-'ARMED IMPACT-FIRED FUSE Filed Aug. 12, 1944 GEORGN ATTORNEY NTOR BREEZE Loro A. anos/WELL Patented Feb. 21, 1950 PRESSURE-ARMED IMPACT-FIRED FUSE George E. Breeze, Uncasville, and Lloyd A. Brockwell, New London, Conn., assignors to the United States of America as represented by the Secretary of the Navy Application August 12, 1944, Serial No.. 549,208

1 Claim.

This invention relates to a water-armed fuze y for detonating an explosive charge and is particularly directed to a novel water-armed fuze of the contact type for use below the surface of the water.

The fuze of the present invention is of the type disclosed in Patent No. 2,419,815 issued to George E. Breeze et al. The type of fuze there shown comprises a detonator normally disposed in a safe, spaced relation to a booster but movable into a recess in the booster when the fuse is armed, the desired movement being effected by a piston operable under the pressure of the water. It has been found that occasionally fuzes of this type do not arm properly because the detonator is out of alignment with the booster recess and therefore cannot slide home into the booster. Also, the piston sometimes binds in its cylinder and thereby impedes the arming action. Fuzes of this type, as made heretofore, have the additional disadvantage that a considerable overall length is required to space the booster and the detonator sufficiently for safety in the unarmed position.

One object of the present invention, therefore, resides in the provision of a novel fuze which overcomes these disadvantages of prior fuzes of the type described.

Another object of the invention is to provide a fuze of novel construction in which a substantially continuous barrier is interposed between the detonator and the booster in the unarmed position, whereby the fuze may be made in a more compact form.

These and other objects of the invention may be better understood by reference to the accompanying drawing, in which Fig. 1 is a side elevation of a projectile having one form of the new fuze, part of the projectile being broken away to show the fuze;

Fig. 2 is an enlarged longitudinal sectional View of the fuze;

Fig. 3 is a sectional view on the line 3 3 in Fig. 2;

Fig. 4 is a wiring diagram showing the electric detonator circuit, and

Fig. 5 is a sectional view on line 5-5 in Fig. 2.

Referring now to Fig. 1, it will be seen that the fuze I is located in the nose portion of the projectile I2 and that its axis coincides with that of the projectile. The explosive charge (not shown) lies around and behind the iuze.

The fuze as shown in Fig. 2 comprises a housing in the form of a cylindrical tube Illa, which may be made of brass or other suitable material. A

booster charge I4 is located in the rear end portion of the housing and is retained in place by a relatively thick metal ring I brazed to the inside of the housing. The central opening in the ring receives the open end of a thin walled cup I5 which extends rearwardly into the booster, the cup being brazed to the ring and having a form such that the detonator 35 may move into the cup, as will be described in detail presently.

The tube lila is open at its nose end to receive the fuZe parts, and when the parts are assembled in the tube, its nose end is closed with a cap I1 which is tightly wedged into the tube until a shoulder I9 on the cap engages the tube end, and is soldered thereto to form an airtight cell. The fuse is retained in the projectile I2 by external threads on the cap which are received in a correspondingly vthreaded opening in the nose of the projectile casing.

To support the operating parts of the fuze and permit movement of the detonator into the booster, a subassembly generally indicated at 22 is provided. The subassembly includes a liber, resin impregnated cylinder 24 having on its nose end an external annular flange 25 which ts loosely in the housing. Adjacent the nose end of cylinder 24 is an expansible bellows 28, the bellows being secured at its closed end to the cylinder and at its open end to the cap I'I, where the bellows communicates with a central opening 29 in the cap.

The detonator 35 is electrically red by current from a water activated sea cell 3l! mounted inside the bellows 28 and movable with the cylinder 24. The nose end of the cell 30 has a protruding shank on which is threaded a cap nut 32 seated in a central opening in the cap. In arming the fuze, the nut 32 is removed, taking with it the threaded shank and thus pulling ofi the nose end of the cell. As a result, the cell is exposed to sea water which causes it to become activated and generate an electro-motive force. The nut 32 forms a tight seal with cap I'I and prevents the sea cell 30 from becoming activated if the projectile is accidentally flooded with water.

The steel case of detonator 35 is supported at its front end in the cylinder 24, while its rear end is tapered, as shown at 35a, and is in alignment with the booster cup I6. The rear end portion 35a. of the detonator case is considerably thickened longitudinally and, when the fuze is unarmed, lies in the plane of the ring I5 to form with it a substantially continuous metal barrier between the detonator and the booster. This barrier prevents the booster from exploding if the detonator fires prematurely. The detonator is carried within the steel case and res through lateral ports 36 when detonated. In the unarmed position of the fuze, the bellows 28 is collapsed and holds the cylinder 24 and detonator 35 in the safe position shown in Fig. 2, with the help of a spring 24a coiled' around4 the cylinder and interposed between the flange 26 and the ring l5. When the cap nut 32 is pulled off, however, and the projectile enters the water, the water flows through the central opening in cap il and fills the bellows, thereby expanding it to force the cylinder 24 to the rear and move the detonator case home into the booster cup i6.

A normally open safety switch 31 carried by the cylinder 24 is closed at the time the cylinder moves the detonator to the armed position. The safety switch comprises a pair of spring contacts 38 and 39 (Fig. 4) normally open but pushed against eac-h other due to engagement of the switch with the ring l by the bellows-actuated cylinder 24. Movement of the detonator case into the booster cup I6 is limited by a shoulder 4t on cylinder 24 which moves into engagement with the ring I5 and at the same time protects the switch arms 38 and 39. When the switch 31 is .operated as described, the electric firing circuit for the detonator is partially closed (Fig. 4) The switch 31 per se forms no part of the present invention and, therefore, its details are not shown. However, the details of a switch suitable for the purpose are disclosed in Patent No. 2,419,815 issued to George E. Breeze et al.

The ring circuit includes the sea cell 30, the detonator 35, the switch 31, a preloading resistance 4.2, which speeds up activation of the sea cell, and, a, ring switch 4I. This ring switch 4l comprises a pair of electrodes in a small glass envelope containing a. large globule of mercury, a switch of this form being disclosed in the aboveidentified application of G. E. Breeze et al. When the projectile moving through the water makes contact with a target, the resulting jar or impact is sufficient to shake the mercury and momenhandle because of its multiple safety features. The extended rear end 35a of the detonator casing, together with the ring I5, provides a heavy barrier between the detonator and the booster suflicient to prevent explosion of the booster if the detonator should fire accidentally, and the booster can be exploded by the detonator only when the latter is moved into the booster cup I6 by operation of the bellows. By tapering the extended end 35a of the detonator casing, the casing is caused to move freely into the booster under action of the bellows without jamming, even when the casing is inaccurately aligned with the booster cup I6. The bellows 28 serves to move the subassembly 22 positively to its armed position without binding and also prevents water from reaching the fuze parts in the cylinder 24.

We claim:

In a fuze having a detonator and a booster, a metal casing for the detonator adapted to fit into a recess in the booster but normally withdrawn from the recess, the casing having a solid, extended and tapered end adjacent the booster and also having side walls containing lateral ports through which the detonator is operable to explode, a metal ring between the booster and the detonator and through which the casing is movable into the receptacle, the ring and said end of the casing normally forming a generally continuous barrier between the booster and the detonator, and means for moving the casing through the ring and into said recess, said tapered end of the casing being operable to guide the casing into the recess upon movement of the casing by said means.

GEORGE E. BREEZE. LLOYD A. BROCKWELL.

REEERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 323,524 Paulus Allg. 4, 1885 1,368,569 Minkler Feb. 15, 1921 1,617,674 Dieter Feb. 15, 1927 1,693,661 Ogden Dec. 4, 1928 FOREIGN PATENTS Number Country Date 117,106 Great Britain July 5, 1918 

